title: Improved treatment of the breast and supraclavicular fossa based on a simple geometrical principle.
abstract: In breast cancer, nodal irradiation has become routine, but adds time and creates concerns for field overlap if the "match" is not accurate. We developed a technique to address these issues by using only one isocenter for both areas. Tangents are designed at simulation. The isocenter is then shifted to the upper border of the breast using a straightforward geometrical calculation. After determining the new isocenter, fields are recreated wherein the tangents are treated with a quarter beam and the supraclavicular field fashioned with a half-beam block. The gantry, collimator, and couch angles of the supraclavicular field are adjusted to achieve an accurate match. Ten patients were evaluated. Doses to the spinal cord and brachial plexus were lowered relative to conventional techniques. The hot spots were not augmented. In comparison with standard arrangements, setup time decreased. Accurate matching was consistently achieved and verified by portal imaging. A new approach for treating the supraclavicular fossa is easily executed. Advantages include negligible doses to the critical neural structures (i.e., spinal cord and brachial plexus), optimized matchline, and reduced setup time.
authors.affiliation: Institute of Radiotherapy, Department of Medical Oncology and Diagnostic Imaging, Tel Aviv Medical Center, Tel Aviv, Israel. dalia.yavetz@gmail.com
authors.forename: Dalia
authors.initials: D
authors.lastname: Yavetz
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Corn
authors.forename: Diana
authors.initials: D
authors.lastname: Matceyevsky
authors.forename: Rahamim
authors.initials: R
authors.lastname: Ben-Josef
authors.forename: Viacheslav
authors.initials: V
authors.lastname: Soyfer
authors.forename: Igal
authors.initials: I
authors.lastname: Bershtein
authors.forename: Moshe
authors.initials: M
authors.lastname: Inbar
authors.forename: Ilan
authors.initials: I
authors.lastname: Ron
authors.forename: Irena
authors.initials: I
authors.lastname: Jiveliouk
authors.forename: Dan
authors.initials: D
authors.lastname: Schifter
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000532:radiotherapy*; D008875:Middle Aged; D056888:Patient Positioning; D011835:Radiation Protection / Q000379:methods; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome